Highly regioselective hydroaminomethylation of long chain alkenes catalyzed by Rh–BISBIS in a two-phase system

The hydroaminomethylation of long chain alkenes with secondary amines in aqueous/organic two-phase system catalyzed by rhodium catalyst precursor and water-soluble diphosphine ligand BISBIS (sulfonated 2,2′-bis(diphenylphosphinomethyl)-1,1′-biphenyl) was investigated. The result showed that the use of BISBIS improved the reaction activity and especially regioselectivity for linear amine significantly compared with the monophosphine ligand TPPTS [P(m-C₆H₄SO₃Na)₃], the ratio of linear to branched amine was up to 83.     

Ruthenium carbonyl-complex catalyzed hydroaminomethylation of olefins with carbon dioxide and amines

Use of carbon dioxide as a reactant instead of toxic carbon monoxide in the hydroaminomethylation reaction sequence is demonstrated for the first time. The present Ru₃(CO)₁₂-catalyzed one-pot protocol includes reverse-water–gas-shift (RWGS) reaction, hydroformylation reaction and reductive amination which finally leads to secondary and tertiary amine. The influence of various reaction parameters including the effects of catalytic promotors and phase-transfer-catalysts has been investigated. Finally, an optimum reaction conditions were found by suppressing the major side products to have a variety of amines in excellent yields (up to 98%).     

Hydroaminomethylation of fatty acids with primary and secondary amines — A new route to interesting surfactant substrates

The rhodium catalysed hydroaminomethylation of the unsaturated fatty acid derivatives oleic acid ethyl ester (1) and oleyl alcohol (2) with the primary amines hexylamine (3) , benzylamine (4) , aspartic acid diethyl ester (5) and valinol (6) , and with the secondary amine morpholine (7) , respectively, proceeds with good to excellent yields. Using primary amines the structure of the reaction products depends on the stoichiometry of the reactants. Performing the reaction of (1) with (3) with an excess of the amine compound the corresponding secondary amine (9) (1:1‐adduct) was observed. Working with a 2‐fold excess of (1) the tertiary amine (16) (2:1‐adduct) was the main product.     

Hydroaminomethylation of the Renewable Limonene with Ammonia in an Aqueous Biphasic Solvent System

With the hydroaminomethylation of the natural compound limonene with ammonia an atom‐economic method for the synthesis of primary amines is described. This tandem reaction allows the direct conversion of the unfunctionalized monoterpene to a valuable amine product. For the first time, ammonia served as substrate to result in a maximum primary amine yield of 25 %. To overcome unwanted side reactions, a biphasic solvent system was used, consisting of an aqueous catalyst phase and an organic product phase. As catalyst the water‐soluble transition metal complex [Rh(cod)Cl]₂/triphenylphosphine trisulfonate was chosen. In combination with the surfactant hexadecyltrimethylammonium chloride it provided a good phase interaction and the possibility for easy phase separation after the reaction.